package com.buba.springcloud.servlet;

import java.util.HashSet;
import java.util.Set;

public class User {
    //利用hashset的特点，自动排除相同的数据
    private static Set<String> list=new HashSet<>();

    public static void add(String id){

        list.add(id);
    }
    public static void remove(String id){
        list.remove(id);
    }
    public static int getSize(){

        return list.size();
    }
}
